Means fob controlling the charge of storage batteries



F. s. BEETEM MEANS FOH CONTROLLING THE CHARGE OF STORAGE BATTERIES July12, 1932. 1 Original Filed July 25. 19:50 v Re. 18,5 16

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Reiuued July 12,- 1932 PATENT- OFFICE FRANK G. BEE'IEM, F IHILADELPHIA,PENNSYLVANIA v MEANS FOR CONTROLLING THE CHARGE OF STORAGE BATTERIESOriginal No. 1,833,849, dated November 24, 1931, Serial no. 470,696,filed July 25, 1930. Application for reissuefiled December 30,

My invention applies to systems in which a storage battery is chargedfrom a suitable generator at either of two charging rates, dependingupon the battery voltage, the charg- 5 ing rate being reduced from thehigher rate to the lower'rat'e at a certain predetermined batteryvoltage. My invention is especially applicable to systems in which acharging generator isconnected to the storage battery by means of anautomatic switch or cut-out designed to close when the generatorvoltagereaches a certain value and to open again when the generatorvoltage drops to some lower value. p

An object of-my invention is to provide a voltage responsive relayadapted to reduce the charging rate from the higher value to the lowervalue and toprovide means whereby the exciting coil of this relay isdisconnected until after the generator is connected to the battery bymeans of the automatic switch. ()ther objects of the invention'are toprovide apparatus for carrying out the desired objects which shall besimple in construction, inexpensive to manufacture and reliable inoperation. My invention will be more clearly understood by reference tothe accompanying drawing in which is shown diagrammatically a systemdisclosing one embodiment of my invention applied to a combination ofbattery and charging generator, the latter of the third brush type suchas is generally employed for starting and lighting systems onautomobiles.

In the drawing, 1 is a charging generator of the third brush typeconnected to the circuit 2, 3, its field coil being shown at 21. Thisfield coil is connected between the third brush of the machine and theconductor -3 0 through a fixed resistor 20. The resistor 20 is normallyshort circuited through the contacts 18 of the voltage responsive relayR,

.which is' provided" with a magnetic core 15 r and an armature 17pivoted at 22. The core 15 is rovided with an exciting coil 16 connecteacross the circuit 2, 3 through the con tacts 9 of the relay A. Thecontact 18 rnounted on the armature 17 makes contact with a bimetallicstrip 19 so arranged that at higher temperatures the free end of thisbi- 1931. Serial No. 584,005.

metallic strip rises, moving the armature 17 nearer to the core 15, thusreducing the air gap and causing the armature to be attracted into itsupper position to break the contact 18 at a lower voltage than thatrequired when the temperature is low.

The closing of the contacts 9 of the relay A is determined by thecombined action of the voltage coil 4 connected directly across thecircuit 2, 3, and the series coil 5 which carries the current deliveredfrom the generator to the battery when the contacts 10 of the automaticswitch B are closed.

The automatic switch B is of the well known type, having a core 14, ashunt coil 6 anda series coil 7. The shunt coil 6 is connected acrossthe circuit 2, 3, and when the generator reaches the voltage for whichthe automatic switch or cut-out B is adjusted, the excitation of thecoil 6 is suflicientto lift the armature 12 against the force exerted byspring S and close the contacts at 10, connecting the generator 1 to thebattery 8.

Referring again to the relay A, the adjustment of the relay A and theautomatic switch .B is such that the excitation of .the coil 6 on theswitch-B will always close the con,-

"tacts 10 before the excitation of the coil- 4 A, and the excitation ofthis coil added'to that of coil 4 will be sufiicient to close thecontacts 9, thus completing the circuit of the exciting coil 16 of relayR. Atthe begining of the charging period, the voltage across the thecontacts at 18. As the battery becomes 4 circuit 2, 3 will not'besufiicient to cause the more fully charged, the voltage will rise untilat a certain predetermined voltage the contacts 18*will be opened andthe charging rate reduced by the insertion of the resistance 20 inseries with the field coil 21.

The. object of the arrangement shown in this drawing may be explained asfollows:

It is desirable to connect the coil 16 on the generator side of theautomatic switch B so that. when the generator is not in operation andthe automatic switch is open, the coil 16 imentioned switch and saidbattery, said automatic switch being 'adjustedto'close'before will bedisconnected from the battery and will not constitute a continuous drainof current from the battery-when the generator is idle. However, whenthe coil 16 is con-, nected across the generator, the generator voltagemay rise to an excessive valuesuflicient to attract thearmature 17 andopen the contacts at 18 before theautomatic switch 13 is closed. Thiswill start the charging of the battery at the low rate instead of thehigh rate whereas it is always desirable to start the charge at thehigher rate. In order to avoid this difficulty, the relay A has beenintroduced and so designed that the circuit of the coil 16 cannot beclosed until after the automatic switch B has closed. As soon as theautomatic switch B closes, the voltage of the generator will drop tothat of the battery, and as explained above, this voltage will not besufficient to actuate the relay R until the battery charge has beennearly completed.

It will be noted that the relays A and B are similar in construction andperformance and in fact they may beidentical in design except for aslight difference in adjustment to insure that the switch B will closebefore the switch A. By making these two switches identical,the cost ofproduction is materially reduced. 7 i

said first mentioned switch closes. v

3. In combination, a storage battery, a charging generator, an automaticswitch adapted to connect the generator to the' battery at apredetermined generator voltage,

means including a voltage responsive exclting coil for adjusting thegenerator field excitation selectively at either a higher or a lowervalue, and a relay having an excitin coil in series with the generatoroutput an adapted to connect said voltage responsive exciting coilacross the generator in response to a flow of current from saidgenerator.

4. In combination, a storage battery, a charging generator, an automaticswitch adapted to connect the generator to the battery at apredetermined generator voltage,

means includinga voltage responsive exciting coil for adjusting thegenerator output.

selectively at either a higher or a lower value, and a relay having anexciting coil in series with the generator output and adapted to connectsaid voltage responsive exciting coil across the generator in responseto a flow of current from said enerator.

F ANK G. BEETEM.

Having described one embodiment of my invention, what I claim and desireto secure by Letters Patent is:

1. In combination, a storage battery, a generator and its circuitincluding a voltage v responsive exciting coil adapted to be connectedacross said generator for adjusting the charging rate to the batteryselectively at either a higher or a-lower value, an automatic switch forconnecting the generator to the battery, a relay adapted to control theadjusting means, said relay having a voltage responsive exciting c011,and means for connecting said 0011 to the clrcuit between I thegenerator and the automatic switch only after said automatic switch hasclosed.

2. A charging apparatus for batteries including in combination, a thirdbrush generoperating. contacts on said armature and on I said bimetallicelement, a coil controlling said armature and adapted to be connectedacross said battery, a switch in series with said coil, a second coilconnected across said battery and controlling said switch, and anautomatic switch connected between said last

